Electrochemistry - Result Question 43

42. Calculate the quantity of electricity that would be required to reduce $12.3 $ $g$ of nitrobenzene to aniline, if the current efficiency for the process is $50 %$. If the potential drop across the cell is $3.0 $ $V$, how much energy will be consumed?

(1990, 3M)

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Answer:

Correct Answer: 42. $(347.40 $ $kJ)$

Solution:

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Change in oxidation number at nitrogen $=4-(-2)=6$

Equivalent weight of nitrobenzene $=\frac{123}{6}$ $ g$

$\Rightarrow$ gram equivalent of nitrobenzene $=\frac{12.3 \times 6}{123}=0.60$

$\Rightarrow$ Theoretical requirement $=0.60 \times 96500 $ $C=57900 $ $C$

$\Rightarrow$ Actual requirement of electricity $=2 \times 57900=115800 $ $C$

$\because \quad V \times C=J$

$\Rightarrow$ Energy consumed $=115800 \times 3 $ $J=347.40 $ $kJ$